I was feeling a bit adventureous today so I bought a bottle of Slick 50 to see if it would make any difference (and at US$50 a bottle, it better should!). While I was happily pooring the stuff in the engine, I noticed that black thingy right next to the filling hole. Being the inquisitive mind that I am, I immediately janked the thing out to have a look and noticed it was very, very dirty. I cleaned it up a bit and put it back. I know this is the Crankcase Valve Vent (well, I knew after I looked it up anyway) but I have no idea what it does. Can anyone explain please? Is it just a simple over-pressure valve? Did I do something really stupid by cleaning it?

Yes, it's just a crankcase pressure releif valve (PCV). And No, You didn't hurt anything my cleaning it. Most people just go buy a new one but, here in the U.S. they are only a couple of bucks.

The valve is precisly weighted to block the vacuum port when no pressure is present. As the pressure builds behind the weight, it is allowed to excape back into the combustion chamber through the PCV vacuum port.

Crankcase pressure is present in all motors. As the rings wear, the blow-by increases and even more pressure is addded to the crankcase. If the PCV valve becomes stuck, your motor will vent elswhere. This "elsewhere" is usually the dip-stick tube and it usually spews a lot of oil with it. Therefore, clean/new PCVs are a good thing.

Always ready to give a $.25 answer for a $.05 question,
Roy

PCV means positive crankcase vent. This device has nothing to do with engine wear. The pcv has to do with relieving the pressure contained within a cavity with a reciprocating mass, ia crankshaft, rods, and pistons turning rapidly inside the block cavity. As the moving parts turn, they draw out side air into cavity and create pressure as they turn. There are several types of PCV valves and act as a one way check valve.
Cleaning this valve and noting it's condition is very good..Replace as required.
Frank R..

One thing I noticed while cleaning it was that it doesn't close completely. Should it? I'm not noticing anything strange while driving the car. In fact, for the past two months it has been running extremely well. For some reason the car has become much more responsive and purrs like a kitten.

Hate to break the news to you, but Slick 50 has less lubrication properties than water.
You just blew $50. LOL I just started a war.

Yeah the PCV valve does get a bit more air venting through it as the motor grows older,shouldn't matter though as long as the valve is opening and closing properly; this will effectivly change the tuning(air fuel mixture)of the engine as the manifold is connected to the crankcase also.Also it's nice to have a PCV valve that works good on a particular engine(yours),I've found some of the brands to work differently,or improperly and cause lousy throttle response as a result.
Oh,almost forgot; it's a check valve,one way flow,letting air into the engine crankcase while the vacume draws to equalize the pulses from the moving pistons.

[This message has been edited by lowCG (edited 04-28-2000).]

I've actually heard lots of good things about Slick 50....

One obvious sign that you've got problems is when smoke comes billowing out that opening while the engine is running.

Under certain conditions Slick 50 equals or even betters water in lubrication, however, water does not leave residue.

[This message has been edited by Phaeton (edited 04-29-2000).]

Yep, I tried it once with a newly rebuilt engine a few years ago, I noticed no difference, none, zilch, nothing. I think it's pretty much proven nowadays that these products with Teflon (including Slick 50) really don't do what they claim. Here is an article that explains why.

http://www.jps.net/gtracer/snakeoil.htm

DuPont doesn't endorse teflon for this use. That allone should tell you something. DuPont only sells Teflon to these scamer because they are forced to by law. When DuPont tried to block sale of Teflon to makers of these products thay got sued and lost. DuPont presently has pending litigation against Quaker State for using the Teflon logo on engine treatment product.

These suits are why you always see it listed genericly as PTFE. Nearly every study has found most of the PTFE ends up trapped in the filter after just one past thru the oil pump. Consumer Reports data on PTFE and other products has even been reviewed by the FTC and other federal agencies.

The Sole perpose of the PCV valve is to force fresh air to be drawn thru the motor and draw off waste vapor in the crank case to prevent corosion and sludge. It is the first "emmision control" device, since it also prevents those vapors from simply going into the air. The PCV valve opens only at a particular range of vacuum.

As old as yours is cliff, i'd replace it. likely the spring is getting weak in it.

Slick 50 is nothing more than ground up teflon powder in 50 weight oil. If you look close, you can actually see the powder suspended in the oil. As mentioned earlier, the particals will just get caught in the oil filter.
Recently, Slick 50 was required by law to remove all claims of mileage increase, reduced wear, etc from their advertising because there was no proof of those claims. The only thing slick about Slick 50 is their advertising.
If you haven't put the Slick 50 in you're car yet Cliff, don't do it. Return it for a refund and buy some Mobil 1 synthetic oil instead.

You know, I've read all these stories about why stuff like Slick 50 doesn't work, and the very first time I had put it in a car (which also happened to be a Fiero) I was very sceptical and didn't expect to notice any change. But much to my suprise I did notice a difference... Two things that became apparant after 50 miles or so, was that the engine didn't get nearly as hot as it used to get, the other was that it was idling much smoother. I had put the Slick 50 in when I had the oil changed. Two years after that (when I had brought the car back with me to Holland), I had another oil change and the mechanic had a look at the oil and asked if had my oil changed a few months ago. When I told him the last time was over 2 years ago, he didn't believe me.

The second car I had put Slick 50 in, was an old Opel Kadett, a small european commuter car, approx 10 years old. When I took it in for a yearly check-up (one year later) I got a call from the garage telling me there was hardly any oil in the engine. Apparantly, I had an oil leak and the guy couldn't understand how I could be driving a car in that condition. There was no apparant damage.

Now, I've put it in the Fiero I currently own. And again the first thing I noticed is that the engine doesn't get nearly as hot as it used to get. I usually drive short distances to my office, which is about 5 minutes of actual driving and 15 minutes of waiting for traffic lights. The engine would always heat up to around 220F and now it doesn't anymore...

Now ofcourse this all could be a coincidence but my experiences with Slick 50 are pretty good...